Question

What I read from gcc manual http://gcc.gnu.org/onlinedocs/gnat_ugn_unw/Output-and-Error-Message-Control.html here is that the command line swich is -gnatv.

But using this switch in MinGW gives: cc1plus.exe: error: unrecognised debug output level "natv"

Answer 1

You can use …

-Wall: all the warnings about constructions that some users consider questionable, and that are easy to avoid)

Activated Warnings:

  -Waddress   
  -Warray-bounds (only with -O2)  
  -Wc++11-compat  
  -Wchar-subscripts  
  -Wenum-compare (in C/ObjC; this is on by default in C++) 
  -Wimplicit-int (C and Objective-C only) 
  -Wimplicit-function-declaration (C and Objective-C only) 
  -Wcomment  
  -Wformat   
  -Wmain (only for C/ObjC and unless -ffreestanding)  
  -Wmaybe-uninitialized 
  -Wmissing-braces (only for C/ObjC) 
  -Wnonnull  
  -Wparentheses  
  -Wpointer-sign  
  -Wreorder   
  -Wreturn-type  
  -Wsequence-point  
  -Wsign-compare (only in C++)  
  -Wstrict-aliasing  
  -Wstrict-overflow=1  
  -Wswitch  
  -Wtrigraphs  
  -Wuninitialized  
  -Wunknown-pragmas  
  -Wunused-function  
  -Wunused-label     
  -Wunused-value     
  -Wunused-variable  
  -Wvolatile-register-var 

-Wextra: This enables some extra warning flags that are not enabled by -Wall

  -Wclobbered  
  -Wempty-body  
  -Wignored-qualifiers 
  -Wmissing-field-initializers  
  -Wmissing-parameter-type (C only)  
  -Wold-style-declaration (C only)  
  -Woverride-init  
  -Wsign-compare  
  -Wtype-limits  
  -Wuninitialized  
  -Wunused-parameter (only with -Wunused or -Wall) 
  -Wunused-but-set-parameter (only with -Wunused or -Wall)  
  *(and some more)*

See GCC Warning Options for more informations.